Linkage system

Abstract

A linkage system which offers high rigidity and good assemblability and producibility, and enables parts such as rotary transmission components and actuators to be readily installed. A linkage system includes an input member disposed on an input side, an output member disposed on an output side, and three or more link mechanisms, each link mechanism consisting of end links rotatably coupled to the input member and the output member, respectively, a center link rotatably coupled to the end links on the input side and the output side, and four revolute joints by which the end links are rotatably coupled to the input and output members, and to the center link. The link mechanism being geometrically identical with respect to a center cross-sectional plane relative on the input and output sides. Each of the revolute joints of the link mechanism includes bearings that support at both ends of the revolute joint.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a linkage system used, for example, for a joint of an articulated robot that performs complex processing or handling of goods in a three-dimensional space at high speed and with high precision. [0003] 2. Description of the Related Art [0004] For example, Japanese Patent Laid-Open Publication No. 2000-94245 discloses a linkage system with a parallel link mechanism that performs complex processing or handling of goods in a three-dimensional space at high speed and with high precision. [0005] The parallel link mechanism adopted in such a linkage system includes a plurality of links that connect a base plate and a traveling plate and cooperatively extend and retract to change the position and orientation of the traveling plate relative to the base plate. Tool is attached to the traveling plate of the parallel link mechanism, while a workpiece is held on a table which is designed rotatabl...

AI Technical Summary

Benefits of technology

[0015] Based on the foregoing, an object of the present invention is to provide a linkage system that offers high rigidity and good assemblability and producibility, and enables parts such as rotary transmission components and actuators to be readily installed.

[0017] The bearings that support at both ends of each revolute joint of the link mechanism improve the rigidity at the bearings and of the link mechanism itself. The bearing structure enables the link mechanism components to be detachable at parts other than the revolute joints and improves assemblability and producibility of the link mechanisms, which in turn enables size reduction of the link mechanisms.

[0018] The revolute joints of the link mechanism may preferably be detachable from the links. This makes it possible to disassemble the bearings in the revolute joints into separate units. Each component can then have a simple shape and be produced more easily, leading to improved mass-producibility.

[0029] In the foregoing configurations, a linear drive mechanism can be provided to any one of the input member, the output member, and the center links, to achieve end position control of the output member whereby a member attached to the output member can more readily be contacted with a predetermined point.

Problems solved by technology

On the other hand, if the operating range of the traveling plate needs to be increased in the parallel link mechanism, the links have to be extended because each link has a relatively small operating angle range, and the entire mechanism and then the system itself become bulky.

Further, because of relatively low rigidity of the entire mechanism, the weight of the tool, or the load capacity of the traveling plate, has to be limited to a small range.

For example, the rigidity of the link mechanism is not satisfactorily high because of cantilevered structure at the revolute joints thereof.

The assemblability of the link mechanism is poor because the input-side and output-side link hubs, end links, and center links are coupled to each other with revolute joints.

Furthermore, because these parts each have a complex shape, they do not lend themselves to be readily produced.

Another problem was that there was little freedom of installation of the rotary transmission components and actuators because the space left in the link mechanism was small.

It was hard to install other necessary parts that were large, such as rotation angle sensing means for measuring rotational angles of the input-side end links.

Images